With the development of electronic industry, electronic components operate at high frequency and speed, and the faster an electronic component operates, the more heat it generates. Excessive heat will result in the electronic component operating unstably, and even damaging the electronic component. So the heat must be removed quickly to keep the electronic component operating stably. Generally, heat dissipation devices are provided to the electronic component for dissipating heat.
Referring to FIG. 5, a conventional heat dissipation device comprises a heat sink 100. Which comprises a flat base 122 and a plurality of parallel fins 124 arranged on the base 122, and a fan 126 located above the fins 124 for providing airflow to the fins 124. The configuration of the heat dissipation device provides large heat-dissipating area. However, due to high density of the fins 124, large resistance to the airflow is inevitably generated, which results in the speed of airflow being decreased thereby decreasing the heat dissipating efficiency of the heat dissipation device. Provided lowering the density of the fins 124 to reduce the resistance, the heat-dissipating area can also decreases, accordingly, the heat dissipation efficiency decreases. Additionally, the airflow produced by the fan 126 flows spirally and downwardly, which is inconsistent with the extending direction of the parallel fins 124. Thus the airflow cannot contact adequately the fins 124. As a result, heat-exchanging efficiency between the airflow and the fins 124 is lowered.
Thus, an improved heat dissipation device which overcomes the aforesaid drawback is desired.